HtmlEditorExtender error only on product server

Hi all,

I'm using an HtmlEditorExtender in my page, with the upload image button. When I test the code in localhost, if I try to insert an image all works good, but if I test the same code on production server online, I receive an error during the image uploading. The error is not in the code, but is written in the upload image mask: "[ ... ] image 100% (error)".

Where I could chack the error origin?

This is my web.config:

<system.webServer><validation validateIntegratedModeConfiguration="false"/><handlers><add name="AjaxFileUploadHandler" verb="*" path="AjaxFileUploadHandler.axd" type="AjaxControlToolkit.AjaxFileUploadHandler, AjaxControlToolkit"/></handlers><security><requestFiltering><requestLimits maxAllowedContentLength="4294967295"/></requestFiltering></security></system.webServer><system.web><httpHandlers><add verb="*" path="AjaxFileUploadHandler.axd" type="AjaxControlToolkit.AjaxFileUploadHandler, AjaxControlToolkit"/></httpHandlers><httpRuntime requestValidationMode="2.0" executionTimeout="90" maxRequestLength="4194000" /><trust level="Full" /><sanitizer defaultProvider="HtmlAgilityPackSanitizerProvider"><providers><add name="HtmlAgilityPackSanitizerProvider" type="AjaxControlToolkit.Sanitizer.HtmlAgilityPackSanitizerProvider" /></providers></sanitizer></system.web>

Thank you for any help.

Igor